This research project addresses the need to develop an objective, portable, and inexpensive measurement method for determining the accessibility of indoor and outdoor surfaces. Current technical specifications are inadequate, and comprehensive standards are lacking for surface accessibility for persons with disability. In Phase I, five different portable devices that measure surface firmness were developed and evaluated. One device, the tire penetrometer, was demonstrated to be accurate and reliable for measuring surface firmness. In Phase II, the tire penetrometer will be refined and an additional measurement method will be developed to provide thorough and valid measures of surface stability. Repeatability of the device measurements will be demonstrated by the same and different operators. Measures will be validated by comparisons with wheelchair rolling and turning resistance measures recorded in a controlled laboratory setting using the SMARTwheel. The methods developed in this project will make it possible, for the first time, to objectively assess surface accessibility of indoor and outdoor surfaces. Such measures will enable standards organizations to develop specific guidelines for surface accessibility. It is expected that objective measures and specific guidelines will lead to improved accessibility for people of all abilities. PROPOSED COMMERCIAL APPLICATION: A portable surface assessment device for measuring the firmness and stability of surfaces will be made commercially available to enable field testing of surfaces to determine whether or not they are accessible. The device will also enable field testing of outdoor recreation access routes and trail surfaces to determine their degree of accessibility. In collaboration with Dr. Rory Cooper's lab, the SMARTwheel and associated equipment and software will be made available as a package for larger manufacturers or test labs that desire the in-house capability to perform full service surface testing.